Primary fallopian tube carcinoma

Primary fallopian tube carcinoma is an extremely rare malignancy that arises from the fallopian tube. It accounts for ~1 (0.2-1.1)% of all gynecological malignancies (least common of all gynecological malignancies ³).

Epidemiology

The estimated incidence is at ~3-4 per million women ³. It typically presents in post-menopausal females (peaks at 6^th-7^th decades).

Clinical presentation

Most patients are asymptomatic or tend to present with non-specific or insidious symptoms. The symptoms are complex, comprising of an intermittent profuse serosanguineous vaginal discharge, colicky lower abdominopelvic pain relieved by the vaginal discharge, and an adnexal mass (present in ~15%). This clinical constellation is termed the Latzko triad ^13,14. 

Pathology

The pattern of growth can be nodular, papillary, infiltrative, or mass-forming. 

Location 

Most primary fallopian tube cancers arise from the ampulla with endoluminal growth that leads to obstruction and distension of the fallopian tube (hydrosalpinx), which explains why the majority of these patients are rarely asymptomatic in contrast with those with ovarian cancer. 

Bilateral involvement occurs in ~20% of cases, mainly in advanced disease ¹.

Subtypes

• papillary serous adenocarcinoma

  • most common histological subtype

  • can be histologically identical to a serous cystadenocarcinoma of the ovary

• endometrioid carcinoma

• transitional cell carcinoma

Markers

Serum CA-125 levels are often elevated ^6,8.

Radiographic features

Advanced tumors are difficult to differentiate from ovarian tumors on imaging. The presence of a hydrosalpinx can be a useful feature.

Ultrasound

While being non-specific, it may be sonographically identified as a complex cystic mass involving the fallopian tube with papillary projections ^10,11. 

MRI

While signal characteristics are non-specific, they generally are as follows ^1,3:

• T1

  • solid tumor portion is usually of low signal 

  • if there is an associated simple serous fluid containing hydrosalpinx, this may be low signal 

  • if there is an associated simple hemorrhagic fluid containing hydrosalpinx, this may be high signal 

• T2

  • solid tumor component is often homogeneously or heterogeneously low or of intermediate signal  

  • if there is an associated simple serous fluid containing hydrosalpinx, this may be of high signal

• T1 C+ (Gd): solid portion often demonstrates enhancement 

Staging 

See staging of primary fallopian tube carcinoma

Treatment and prognosis

Compared with ovarian carcinoma, fallopian tube carcinoma tends to present at an earlier stage but has a worse prognosis, stage for stage ². However, the better overall survival of fallopian tube carcinoma may be on the basis of an earlier stage at presentation ⁴. Treatment generally consists of surgical debulking followed by chemotherapy.

Differential diagnosis

For a mass involving the fallopian tube, differential considerations would be:

• tubal ectopic pregnancy: women of childbearing age and elevated β-hCG

• primary ovarian cancer (especially ovarian epithelial tumors) with involvement of the fallopian tubes

• infective of inflammatory conditions

  • pelvic inflammatory disease +/- pyosalpinx